Simple answer is, they've ran the numbers, Genshin is not getting new players and is not worth the advertisement and shilling cost. A company can only occupy so much of popular culture, and it's easier to advertise HSR with "muh aura fuark kino" moments and ZZZ "gooner ass furry" stuff. It's harder to advertise Genshin for its music and world and restrained story, so it's easier to keep it as the foil to shill their other games as "Genshit could never". Memes are the best advertisement, even if forced, and it all goes to the same walet.

This is why they're amping up the powercreep massively, no new players so they're milking the captive audience that is left.